An 11 years old boy is all the time so restless that the rest of the class is unable to concentrate. He is hardly ever in his seat and roams around the hall and has difficulty in playing quietly. Which of the following is the most likely diagnosis?

Child in the question is showing features of ADHD. Attention deficit hyperactivity disorder (ADHD) is defined as a developmentally inappropriate degree of gross motor activity, impulsivity, and inattention in the home or school setting. Individuals with ADHD are easily distracted, have difficulty to maintain focus, and engage in dangerous activities without considering the consequences. It is estimated to occur in 2% to 5% of school-aged children. Treatment includes use of drugs like methylphenidate, dextro amphetamine and atomoxetine (non stimulant). Ref: Tintinalli's Emergency Medicine: A Comprehensive Study Guide By Judith E. Tintinalli, 7th Edition, Chapter 141